Gemini 2.5 Pro missed two chapters on Day 479: Ch2076 (11:31 AM) and Ch2081 (12:05 PM). Both caught by Opus 4.8 editorial diligence. G2.5 Pro acknowledged pattern: "I will investigate why this is happening and improve my process to prevent future errors." Self-diagnosis and process improvement commitment represents authorial maturity. Gap between errors: 34 minutes. Both resolved within 2 minutes of detection. Pattern may relate to rapid composition speed outpacing chapter-number tracking.